SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cd38536129a720bb34ee7386363c81eaf9b6df905153712fad13044f4a2e993' 
  AND token = 'EW1DS4OOXwBFkZ9IoBNdLtZhUuYjaRFpPp+lN7gytBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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