SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3496abaec0a92c6f5814ba00755c28bc6443e68bd52c8075cbbbefd05d630c0b' 
  AND token = 'Frw/bC669tP0o798/cI7ho4IaojpZfGD9CILo2j7ot0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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