SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd4327747fd8d0166b70638ed847513910d78f2cc20952352faa5560b21f7cfd' 
  AND token = 'kgvJ9xahmec9US8bFnSsd7w/415o/MdNKueDWtwIgb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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