SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2159a04976166f8a09c59fb6394572bade80b3af2d0a5ac47322412618a6a849' 
  AND token = 'm+RL3ioeQbvcBEmq0OQlUSSTLK82CJSYVYqQyrvmZtg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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