SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ddb794f1c7f9d5d80ce38007396354024ab260e97a35376885628aecf10136c' 
  AND token = 'G8hms7rw+d7wsrsVkSaGqovGM6ixXxlPZvvfE0/A/uI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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