SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e97841cd1939172f3261befa36aa82ed6dff730daa675de8909054c0466b9e9e' 
  AND token = 'RU4vP+pTSeHczXBZ4bXlIIEbqq+dhMU3qNeFKyW3z58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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