SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fc01bfea3d1a3e17d16b3c5633916e347bff0f953efc1983dc071661f4d9612' 
  AND token = 'umUwIRMh8NATapMlxCndzHK2thiMkL8oSa1dimCoSI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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