SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '527bfea278802506048712da5f74ad26ca943275c1880f15a4bd493e6a5009ea' 
  AND token = 'wrPw3hxMaXW8humkP9jRHQc4AdoQAi0hYxvcXlUjPAM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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