SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '638e5586732ce5592523e1b278a1443c2258f6bf6aeb74e8e0b64572150f478c' 
  AND token = 'pGewWmDSAgr3LdgmGeB2HtOPz94DJ/4Xpumjig43+ZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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