SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bfe10f68f64cf851052c4f269bc0efa728ccbf23e70b45811585fe66d10de13' 
  AND token = 'IdCMcyEwGsJgkvCl0EZ1FqPDWJ6j53eHZ1sk+h7L1l0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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