SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f415f45f833c2ef489a3ebd74c05737f7440e1ddeff7f8e3275ab938df682a5c' 
  AND token = 'sUwW+y6k2HpmuLVSIdJXqdl6ZRrVzOyl6HwIZfARjTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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