SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'edfde3119a79902fbe8d214704255c54bf65c9cfa612835524da4808ffb0f453' 
  AND token = 'I7aPGVevmjtavaENg4y22Zb6ffC1UTIpt4LPiL1hU9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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