SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfa5a728595cedecb1047ba197893bb2f186343e7e9467206c8275de62548c0b' 
  AND token = 'llepr5XEThCNumZlQ0tI8jARNCAZJAzar21IvaDNu3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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