SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'beb9fd6a787207c368cc15286fa4739d43ac38ffe9da1f5aef2ae4f1b2b483b8' 
  AND token = 'oQI+e/eHJnQaim0bp+0+LUsBa56DnyJ3sZwhe1rWJP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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