SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bfe0a442f19bac6c9193e6a42fdb21b382b6ecb9036a32e62883e847b0fc1f2' 
  AND token = 'yUL1aMifay4IWDfM170HRq3zULzlwxizE/nMuJ7PH10=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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