SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d09398b2965b4a77e89f9347b8b7e7e28b2e76df2fecdcf96bb532b4ea78f50' 
  AND token = 'FU2LDv0PpcEu78aQQeAp+dvoQhCzMucqq2BZjYGbKHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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