SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d22d7a86483eed49467e18e257f22ecc192fba1afa928a906e5fe6c8223ab53' 
  AND token = 'xbq/ot83fReTuGaYerg+M4HGbuJN8QybU21itUBeOwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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