SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '502cd832d2cce70a7aad917688fe03b3c393a40e40db9cada75f183316589350' 
  AND token = 'vdbGtuxxBmJEGd/vKC/gpydcIaMgXmyZZHa1VvP4UdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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