SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57da519c645fa28fcfcdf948fb60d53fd30827fbd8d1b250b0d438db173315eb' 
  AND token = 'XLNkuHyqJdCubqq1EfURrXAONd+Kmv8b4YqN9FSgkwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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