SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b61491ffdf4f1435e745864efa9070d2165c999796773ff09a855de13d6b8d24' 
  AND token = 'sBKznRt2fVSXpCasZA6zZ/4VJ6BMgeFlw7KKVc22YSw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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