SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93c2798cb51301daa980fc62fab78e80bcd2e89f3687f239c695d471b2773106' 
  AND token = 'LQDePtiPTQVf9O+M9I1pftruDyrQ+5VPqppuxlh2Pj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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