SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9fba960235bf408199ad2db1aa187eb38cfbbc445c570760ed5479ad2fdf50f' 
  AND token = 'l9k0ckZ9o3bs3ozhtnp61RVYbFrQhwNTOnsDBKPDsTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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