SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a4e0efe52fd8873e53f8865a9a8caf8aaaf6a314daaa9c1a4a4a4d9e4e158d1' 
  AND token = 'lM804kybNwynFQlmqrBpu55+y+IVxr1seTUJfacFGlc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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