SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70963802abddcec5e655ede265f808fb410a3ab14544176877316968ed6f0da8' 
  AND token = 'xVzXVyqzGL9wBFAETRDZWSTZ3fgaq+9jNG6yxer9o/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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