SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5307e17a3e1f5f796f321641113d41c31f199b6dcbb81a7bcca16e8187ff7fd' 
  AND token = '7dGa6jKtVyFafiJrC3URbRxb3XNY8BL1a+64konfUSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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