SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '438cb81329c7c14471e24db6ec6555f81aca1927dfb97029848eb1fb17cad12e' 
  AND token = '/UY74pL/gNKCL54vXhhiJCfZ9DsBLbBI+cUuVU4W4cE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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