SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6f163f6dab0fdf78b0ea020f77a436d4537ee93b35e7510290bedd88a674861' 
  AND token = 'RvyjbFoUmyL+h0NX2GWBLHNJ2Gm9n3wxv+ltFjFA9HQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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