SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c999128fd430ad8849efa73b9bdcb6bf4d6baa06958308ceacf9c4ef517460e9' 
  AND token = '+M2DjJkgiLoU+whODXHhlZLI+rD1oEpdGu1W8IAkQd0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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