SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1883028388d16947b56f55abd19cb2ca937f35e6ea19fa9aa9f76b20746b336' 
  AND token = '+gCFFNkUg2IvW8Fld7hbmgwBxSKbTvmpqJGegdMBXvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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