SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdaad1a0e248cd872ac70dc0d1d7e6696e4734903de1228638e8cb716e8b9537' 
  AND token = 'pMvVaz+5pAL2ERwBO3oeEpPvMhPBb1fs0+sPnIKNyc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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