SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ac338c6614dbf633500e302c4267e088e0172e8459f7e1fc2f3a0a6e4188438' 
  AND token = '9vENlqvVPph/+6BDjJlhwZYg7LW4GckQ6R/Q5N/N5S8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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