SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43473e9f6c8f73a210d0f12f12d49c11b7f1529c36284d746ef06b4be4bb61fe' 
  AND token = 'PDRMcCFwiVJjkXxljSQJniPoDFaAYfgO03J/+jeJUsk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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