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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f9fb73ead678d23707b67de7e3e254f6c83104445371d54d820d8059f73c12c' 
  AND token = '0O766U/6fg8ebi8ou3JYSQaaJhlniS2DZFDzt/K0RCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}