SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '853bc044bae7fcbdca99216c0923f08d8cf6fa3d5daf0765979725f062c4124b' 
  AND token = 'BWOo9QyE1qQJZRitpGuow7CDskOhCphu6oPbpd15Xnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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