SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4e0fea46de67a0337d2fbf3cbbdc86035e8daf3828df1c7a9c14fb425f25c82' 
  AND token = '92b7++hJ7KzrazvdJoPMPmyT+wAirkBNRR6fiaI+jE8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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