SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '646dc0359fda8c7642b533ce3b7567624f4177fdd36ded4c90f421bef6fc750d' 
  AND token = 'UBWWaXnzTgSGDbo+hBE7JC1zsmoXmzb5DT6rxtxwqSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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