SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43d8500a3dc9b69361cb2c4dd0d36c233d0aa8dc262eafa8eaea01f5ac06f37c' 
  AND token = 'hrjHNO+5ya/WpYlM+qZH3+CppuU6sui9awdEL3/YL4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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