SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abb60d2ff0441074bec1e283b54beedeaf5fde8794ec12cd7d1d2967e988b120' 
  AND token = 'SaFtlLWK4UqRNmXRjL9p5yZREFfMWhYZBPGuW2673ek=' 
  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"
    }
  }
}