SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '563a9889cc930638a4fee5bea965eb92eb50428b43823494cac7c2ddd2dd3cde' 
  AND token = '8W7JkK5FI/PLw9akbAH9X5Dd1bFALqZjVTfuBFrO9Wo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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