SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '207b2b98568fee367b0a07820665df9aa71c5983a79a3ea278df422709929f52' 
  AND token = 'aWvI1agoxSRPcTz6oWIbXTvXdvRh13pIPOyx4qbvsnI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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