SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3cfd2744b9012acc6a303c68a24dfeeb950257efbad4e9091108237a6d24919' 
  AND token = 'MsKnzcGuNp/QyKxN2CSurqHbB4dFdUCORRo4G15hQzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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