SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03be689fd09ac108d2e536818596d9b9aef799ca7551072f52de25147540aafd' 
  AND token = 'Std2JUnEbbOkhuCW7kFgKnK9EqZRnMDwfRl1hZJMJnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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