SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b84e133edc2e825662db3ba67b5deb7a602f24975b832f53e47be6c674e7fd9' 
  AND token = 'TZkq8TMBmpdJdwAEPYAG4HHhyJ+l35qgmbPdUoOzNes=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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