SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b528c420104267fb916968423cba025da0dfa65fecbbf26ce3e4aa0aa24bd28' 
  AND token = 'eJz++mS7oiiTBIctYmDAbLxR+b1bqJOjE1jwflFtB/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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