SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a34625a645d6c11fd6c4997016aa3a4515f69dec88dfd17a91f7be58d2be846' 
  AND token = 'bZ4fZ//2EFFXd/KcVCzLnPTkIQD2hWZ90YhpoK7gnsI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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