SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c529cf6a2bc6c675b1e17730e3434a47e38cefdc36f318ec6d91e61cd2401f5d' 
  AND token = 'IiiYfXkTjCwsjG83TDbmkJtJ5vrxS4d9iahd1NFCylc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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