SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b0a030334d89f5bf9b05d9276cbc043474c55ccdeb71e59e9a8299bb347d483' 
  AND token = 'k4eNShWQjgkvAfs6RsFLjkebDLAZ0+uC1Sbd9/xUpls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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