SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '902559f926af652880e5f001e11e6e5289a12e43a33ed4a52444fd1b02489fa1' 
  AND token = 'UgH7SvVrIrN8q0yuoagSsbPxoiWqfLp1gWB4bpgr5jI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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