SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ee49fd48921479dffcbba4ffddd371b5ce28d514c08f192195a1f19c97da0d5' 
  AND token = 'cGewaksvp+/mPUmtpzhmiEFvMB4wCBpl+nLxVRw0OkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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