SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87e213928a11a681c85950b798ea5510d8cc9da1451a9f3a2a1414902aabeba4' 
  AND token = 'Tp9u2LJY00/l4IuLBk2dxkXRC5Je1mjJQrnaif4sV+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}