SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91cf221f5a414ae3598747f4ca9b0f879f923089b47e07e7ab24e309023be5ec' 
  AND token = 'LaHcYsjpBorVHFK5Z6L7iuWhfZrGPX3xTqCtHzpzBd4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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