SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2321eb526f3ad3011f2c59d726d1e551b1fa70d080c1957df2b3056dbbcee6f' 
  AND token = '/Uw8B9+DfZAaCUKy7+mfTqG9sHfVJng8hxNyY5gzQII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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