SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aac6a2364931f307b25cf35bbf2bed33da266f2c755bdf3bfdc690b7d296ffa5' 
  AND token = 'bNGpj2aLztqjClAscpdNbXNqT37MN5OoKIBoLPU8Rvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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