SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37a7010f123f74fb20d54f02006b43b3797145e6978e24bfb0889a66fe350fd4' 
  AND token = 'Xad9v1UTVR/nNcUVzLwA6IEmRyxqPTfmJOIF7QVeJkw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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