SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8af4dccf432f7529b7ca52fe8079fc6242280a15949173ed7dae386d0afe199' 
  AND token = '8lhZdhSDxMmB+TcxqN3+xXlpo9r6BoNLjBNTnVvjnKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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