SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ad622b341071a03b9263cc69a1dce988877fa610e0e227ae748155c1b019351' 
  AND token = 'X/MhISFZDSBmZGluffeMnRvzxBKDTmGNRMTUqIvnIeg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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