SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c98839bee683724dce72fd5bab27fad4b68047bb7984dcea10e8f26dc4d4a6d' 
  AND token = 'KVkFFqX01GbLrJPOkT9Y1IPmkUAzssLVcWb4pUhMbjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}