SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3600986acdaa9e7c1e85a554925d1c8fa9641c825e8245128ea4e1c0a8c557b' 
  AND token = 'gDpqHoZCR4cR3GKTNTpmK0OaWfYptwD8W/UOsoPbelM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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