SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5de58a61d392e8017812d246e555e8cacbfb1fb729fefe8b3712a014ca2f29ca' 
  AND token = 'cfWR0dgmVp8RpopJvv+KsbGVnPlgsmQrw5p5p3DpOZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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