SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56aa6b8991558572a44cb8d97a70626f542a6f79992dceed7fa1975e6767272a' 
  AND token = '9LneA9RtvNgFnIAYAik8mkBuAY5uTCtH+1EYU9PSXM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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