SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7770d484841926f6fa602c042bf52df6af54d01631702135a387c43c45f647f1' 
  AND token = 'DqYmwtrtGZ35G9iCE3vYuXqzGRZCquQuDNsix8FVtdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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