SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0368211237ce490d122a20668db996134ea1c32ae97022c1e57e95aa1eee2890' 
  AND token = 'SvSBlWUp/UM/nF8dBNipVlBbrx+i1w5CaeYzBnbbXdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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