SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e71d9867b7197aff239dc6396384049bb27adf167da1afdbffd150cbe5435ec8' 
  AND token = 'bPcWYjbOi3ZX/0DBYjRYCOyTVRJVZ/pfaHO/hmoJQWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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