SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6d030065427b93db656b689b8cd8f36ea13725c3c3432d6eb1762d475e303cf' 
  AND token = '2K+E7+ILJYVeLQWFVkjnkSMmpzKByxzkpH38iYu7vyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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