SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '619712f88ad5f1d199be8b87470dbf31593cf296fc5c723103674a7f096a5017' 
  AND token = 'o6229PpfKCqdW4BfIUEMF6pPj118SRG9LYcAvqzLplY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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