SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6da234d37b865cff4f71ee89dbd205e334062096623710c0b21517081900b2fc' 
  AND token = 'q7bNgeNOVcrkUxszyEGKnzxLzcMQHuS85RUNopK6YB0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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