SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43ae3e9176c8159bd591854b40a0f79163bd254ce7e2aac122f97ae779cc6c30' 
  AND token = 'ZlAqtCDLQOPrnPHGjwnuZ5MuhuLHvMGa6ufUg5lwYHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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