SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0743121566ea7902b8ab350e4c9b54628013804f3fd3689117496fd56d39754' 
  AND token = '5zsJg0v4GapwhjRkl+/ldM7jCDiduQjMU6RIpAl7qVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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