SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b57c92f6df356757b752b3cc07cf30b6f1beadd2c248c6db4014db69910b3f0' 
  AND token = '7Cyc4BjVCSQqEjg4DQ4z3ewkR/LZbELJRnPfpPv924s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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