SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3e4385a8ac6e16943eebdbfadcb3e635d1858f5af1bb12d31fc20bfee521e4b' 
  AND token = '/vwMGXQ5oMfkojQ+iLfNJO/yKNY6kfpMqFk/jpiK/N8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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