SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e15b41e19ca52930c7ae467eaf455a047ce8e7016aa43dd661a30386e9009744' 
  AND token = 'fAoTyJEyrEdKB47chQAhxE3mOrwRpxXvl46BNeg9zcA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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